henry@zoo.toronto.edu (Henry Spencer) (12/13/90)
[This is a heavy news week.] Space station designers trying to decide whether it is more important to get started on the latest redesign or finish the enormously complex series of preliminary design reviews on the last design. NASA favors the latter, on the grounds that much of it will not need to be re-done. [Wanna bet?] X-30 contractor team announces first design cycle should be complete by February. Galileo to take a slow-motion movie of Earth after close approach, taking one frame a minute for a full day to show a full rotation of the Earth in one minute at standard movie rates. The next Earth encounter, two years from now, will include an attempt to get a shot of the Moon and the Earth together. Magellan went on strike :-) for 41 minutes Nov 15, but mapping is expected to resume within a few hours, due to improved spacecraft software and ground procedures. There appears to be an occasional random fault in the attitude control system, which is tentatively blamed for the chaos in August too. Atlantis launched Nov 15, carrying a 22klb eavesdropping satellite said to be aimed mostly at the Gulf area. Titan IV launched Nov 12, carrying a missile-warning satellite for Gulf surveillance. Oddly, although the payload is virtually identical to the warning satellite carried up by the shuttle a while ago, the Titan one is secret and the shuttle one wasn't. 1991 shuttle manifest announced, 6-7 flights. STS-39 in Feb-March will carry the (military) Cirris infrared Earth-observation telescope plus an infrared-background-survey experiment. The Gamma Ray Observatory will go up in April, accompanied by some EVA experiments. SLS-1 (Spacelab Life Sciences) will go in May, another TDRS in June, and another missile- warning satellite in July. Spacelab J, the Upper Atmosphere Research Satellite, and the International Materials Lab will fight it out for the last 1-2 slots. [Prediction: Spacelab J, being Japanese, will lose.] Drawings of a large Soviet design study [note, just a design study, despite some claims otherwise] for a reusable heavylift booster, using four flyback strap-on boosters plus a winged core stage whose large nose-mounted payload fairing would slide back over the body somewhat to give a better shape for reentry and gliding flight. All liquid-fuelled, naturally. The boosters might be derivatives of the Energia strap-ons, while the core stage would use three Energia core engines (Energia uses four). Space Studies Institute [!] signs deal to represent NPO Energia in the Americas, for sales of Energia and Buran launch services and payloads aboard Mir. SSI does not plan any challenge to current US government objections to flight of US payloads on Soviet boosters. [Curious; see next item.] Space Studies Institute signs letter of intent with NPO Energia for launch of SSI's privately-funded Lunar Prospector mission [a lunar polar orbiter carrying a gamma-ray spectrometer]. US and Canadian electric utilities discuss rapid development and launch of a solar-storm-warning satellite to help protect power-distribution networks against high solar activity. The utilities fear possible repetitions of the 13 March 1989 storm, which plunged Quebec into a nine-hour blackout, nearly blacked out the entire US Eastern Seaboard as well, and caused serious malfunctions and significant equipment damage in many areas. A small satellite would be parked in a halo orbit around the Earth-Sun L1 point [where ISEE-3 was stationed for some years]. It would be quite simple, carrying a UCLA magnetometer and an LANL plasma analyzer. The utilities hope that it could be up by 1992, given rapid commercial development, launch on Pegasus, and commercial funding throughout. The utilities hope that NOAA would contribute some money -- and indeed, both NOAA and the USAF are interested -- but government budgeting is too slow for the perceived urgent need. Senior Soviet officials outline a proposal for a US-USSR Mars mission by 2011, calling for a joint space station for unmanned-probe assembly, a reusable tug for hardware transport, a living module for crew transport (built by the USSR), and a manned lander (built by the US), all launched by improved Energias. Image of the Caribbean from China's Feng Yun 1B weather satellite, which apparently uses the same signal format as the US's NOAA/Tiros series. Feature article on MBB's proposal for a German X-plane, dubbed "Hytex", as an experimental precursor to the large hypersonic booster for Saenger. Hytex first flight would be 1998. It would be slightly larger than the X-15, powered by kerosene/hydrogen turbo/ramjets, and capable of Mach 5.5. It is envisioned as a joint European project; Sweden has already joined, Italy is expected to join soon, and other countries are being courted. It is considered a necessary preliminary to Saenger because too many key technologies cannot be tested on the ground. "We can't do propulsion integration on the basis of numeric simulation." Reaching the desired speed would be easy; the tricky part is making Hytex a reasonably good simulation of the Saenger first stage. Originally Hytex was going to be a two-stage mini-Saenger, "...but the aerodynamicists thought they could predict the [staging] effects, so the technology demonstrator did not need to be a two-stage vehicle.". It will fly from the ground, and will be manned. An air launch from an A300 was considered, but it would have complicated the propulsion design badly. Testing within densely-populated Europe was felt to require human pilots, horizontal takeoff, conventional landing, and no jettisoned parts. Materials will be largely conventional for the sake of development schedule. [And to think it took the Germans to do this... This is precisely the sort of thing NASA could have, and should have, been doing 15 years ago.] Plans for increasing the number of US imaging spysats, for the sake of disarmament-treaty monitoring, are on hold due to high cost and debate about the need. Inmarsat approves world's first commercial satellite telephone installation, on a Gulfstream 4 business jet. [The G4 is one of the high-end business jets, meant for long-haul work.] More are expected within weeks, followed by airliner installations. (Several have flown experimentally in airliners.) Racal and Honeywell, together the only supplier, have over 40 orders already. Hubble repairs will require the most ambitious EVA of any shuttle mission yet, tentatively three major spacewalks. The first will replace the solar arrays in an attempt to cure the persistent jitter problem. [They were slated for eventual replacement anyway.] The second would replace the Wide Field/Planetary Camera with WFPC2, which will incorporate correcting mirrors to cope with Hubble's aberrant optics. [WFPC2 was planned for this mission anyway, since the WFPC technology has been advancing rapidly.] The third would be the most interesting part; see 2nd next paragraph. A reboost is not likely to be necessary, although one is planned as part of the second maintenance mission in 1996. NASA would like to do the three spacewalks in one flight, despite the demanding schedule, because of the shortage of shuttle missions and a desire to try out intensive spacewalk operations in preparation for the space station. Hubble's solar-array jitter problems actually appear to be a combination of two separate wobbles, an end-to-end 0.1Hz flexing during sunlight-shadow transitions, and a 0.6Hz sideways flexing during sunlit periods. The first has been dealt with by software, but the second then caused trouble. It is possible that a fully adequate software solution may not be feasible, given the limited computer power available. ESA (which supplied the arrays) and NASA are still trying to sort out the exact nature of the problems. The big question is how to deal with the effect of the aberration on the four "axial" instruments. NASA has ruled out anything that might risk disturbing the major mirrors or contaminating the optics, which are already returning major results despite the problems. One possibility is to just try to deal with the Faint Object Camera and leave the photometer and spectrographs alone. ESA will decide on the best approach to the FOC in January. Building a new one is probably too expensive, but in-space alterations are possible. It would require opening sections that were never meant for on-site servicing, but it is considered less difficult than the successful Solar Max repair in 1984. A more daring possibility is to remove the photometer entirely and replace it by a module which would swing correcting optics into the light path going into the other three axial instruments. There is already a spare axial-instrument box, built as a filler in case one of the instruments was not ready for launch for some reason. The trick will be making the optics boom sufficiently adjustable by remote control on a tight development schedule. [It's a pity to sacrifice the photometer. It is the least-used instrument mostly because it is aimed at exploring a whole new area of observations -- very rapid light fluctuations -- that is simply inaccessible from the ground, and consequently is too poorly known to attract lots of observing interest yet. Alas, this is nevertheless probably the best thing to do.] USAF is ahead of schedule on activating the second Titan IV launch pad at the Cape, set to be used first to launch NASA's Mars Observer in 1992. The first Titan IV launch from Vandenberg will be next year; that pad was accepted by the USAF last month. Letter from Robert J. Naumann of Huntsville: "As the former project scientist for the habitat and laboratory modules, I and others in my working group shared a vision of the space station as a national microgravity laboratory where, for the first time, we would have the power, duration, and laboratory resources to carry out microgravity experiments in an interactive manner..." He's given up on that due to the steady shrinkage of power, facilities, and crew time, and says it's time to push for second best, a man-tended free-flier to at least give continuous high-quality microgravity. Letter from Thomas Armstrong of Paramount, Calif, observing that the X-30 would appear to have a serious control problem in common with the space shuttle: its longitudinal control surfaces are too far aft. The result is that their flap action dominates their elevator action, so pulling the nose up makes the aircraft sink *faster*, while pushing it down *reduces* the sink rate. This happens to some extent on all delta-wing aircraft, but on draggy unpowered craft like the shuttle orbiter, it is a major problem. The landing technique is quite unlike that used to land a normal aircraft, and it puts quite a strain on the pilot. "Add to this an apparent lack of direct forward viewing and the X-30 may prove to be one cubic handful to manage during final flare and landing." -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry
lvron@saturn.lerc.nasa.gov (Ronald E. Graham) (12/14/90)
In article <1990Dec13.062441.16545@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes... >Space station designers trying to decide whether it is more important to >get started on the latest redesign or finish the enormously complex series >of preliminary design reviews on the last design. NASA favors the latter, >on the grounds that much of it will not need to be re-done. [Wanna bet?] A lot depends on how much of the PDR material covers components that would remain themselves intact (although moved around all over the place) after a redesign. Some components will remain more-or-less intact, such as the photovoltaic arrays and the associated beta gimbals (unless something's happened in the project office I haven't heard about yet). In those cases, you probably would want to get the PDR review done. But I'd take my time and have one eye on redesign issues at the same time, just in case. RG
sheppard@caen.engin.umich.edu (Ken Sheppardson) (12/14/90)
In article <1990Dec14.130555.12464@eagle.lerc.nasa.gov> lvron@saturn.lerc.nasa.gov writes: >In article <1990Dec13.062441.16545@zoo.toronto.edu>, > henry@zoo.toronto.edu (Henry Spencer) writes... > >>Space station designers trying to decide whether it is more important to >>get started on the latest redesign or finish the enormously complex series >>of preliminary design reviews on the last design. NASA favors the latter, >>on the grounds that much of it will not need to be re-done. [Wanna bet?] > >A lot depends on how much of the PDR material covers components that would >remain themselves intact (although moved around all over the place) after >a redesign. Some components will remain more-or-less intact, such as the >photovoltaic arrays and the associated beta gimbals (unless something's >happened in the project office I haven't heard about yet). In those cases, >you probably would want to get the PDR review done. But I'd take my time >and have one eye on redesign issues at the same time, just in case. > The PDR concluded some time ago. The review in question is the ISPDR (Integrated Systems Preliminary Design Review) which looks at interface issues, overall system performance, etc. - the sort of things that would change significantly due to a configuration change. Individual components and subsystems were examined during the PDR. =============================================================================== Ken Sheppardson Email: kcs@sso.larc.nasa.gov Space Station Freedom Advanced Programs Office Phone: (804) 864-7544 NASA Langley Research Center FAX: (804) 864-1975 ===============================================================================
smb@ulysses.att.com (Steven Bellovin) (12/15/90)
In article <1990Dec13.062441.16545@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes: > US and Canadian electric utilities discuss rapid development and launch of > a solar-storm-warning satellite to help protect power-distribution networks > against high solar activity. It's nice to be warned, I suppose, but what could be done with the warning?
henry@zoo.toronto.edu (Henry Spencer) (12/17/90)
In article <14122@ulysses.att.com> smb@ulysses.att.com (Steven Bellovin) writes: >> a solar-storm-warning satellite to help protect power-distribution networks >> against high solar activity. > >It's nice to be warned, I suppose, but what could be done with the warning? There are various things that can be done to reduce vulnerability and prepare for trouble, such as shifting loads and starting backup generators to minimize reliance on long transmission lines (where trouble tends to strike). But there are enough extra costs involved that such things are not done without fairly strong assurance that trouble is imminent. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry
szabo@crg5.UUCP (Nick Szabo) (12/18/90)
In article <1990Dec13.062441.16545@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >... >US and Canadian electric utilities discuss rapid development and launch of >a solar-storm-warning satellite to help protect power-distribution networks >against high solar activity. The utilities fear possible repetitions >of the 13 March 1989 storm, which plunged Quebec into a nine-hour blackout, >nearly blacked out the entire US Eastern Seaboard as well, and caused >serious malfunctions and significant equipment damage in many areas. >A small satellite would be parked in a halo orbit around the Earth-Sun >L1 point [where ISEE-3 was stationed for some years]. It would be >quite simple, carrying a UCLA magnetometer and an LANL plasma analyzer. >The utilities hope that it could be up by 1992, given rapid commercial >development, launch on Pegasus, and commercial funding throughout. The >utilities hope that NOAA would contribute some money -- and indeed, both >NOAA and the USAF are interested -- but government budgeting is too slow >for the perceived urgent need. >... This is a great example of why lowering the entry-level costs of space by a factor of 5 -- even if the cost/kg is higher -- is a good business proposition. All of a sudden, we are seeing new industries emerge, in little niches here and there. Solar storm warning was previously a government monopoly for government purposes. Now, companies can afford to launch satellites to suit their own needs. Over the long term, IMHO the number of organizations with access to space will rise by an order of magnitude due to Pegasus. I predict that once consciousness of cheap space access reaches the business community, we will be seeing many more new, small industries like this one emerge. Not all of these will remain small. Way to go OSC and Hercules! -- Nick Szabo szabo@sequent.com "For historical reasons, this feature is unintelligible" The above opinions are my own and not related to those of any organization I may be affiliated with.